Japanese Patent Laid-Open Publication No. 2012-160666, including FIGS. 1 and 2, and paragraph [0078], discloses an LED module (a light source unit) in which a base portion (a fixing portion to a housing) of a light direction converting element which is an optical system for reflecting the light of the LED portion is fixed by three screws (fixing units to the housing) with respect to a case on which an LED portion (an excitation light source) is mounted.